From the changelog:
Changes with Apache 1.3.17 *) Normalize the Netware path names to close a potential security hole in comparing paths when the adminstrator specifies both sys:foo and sys:/foo formats in the same httpd.conf file. [Brad Nicholes] *) Fix an unlikely segfault provided a zero length string in the translate_userdir() call on win32/os2, and accept backslashes in the UserDir directive on those platforms [William Rowe]